Handle hash tables and vectors when reading/writing EIEIO objects
* lisp/emacs-lisp/eieio.el (eieio-override-prin1): EIEIO objects
printed with `prin1' can no longer be read with `read'. Make sure
they are printed with object-write instead, even when they're inside
hash tables and vectors.
* lisp/emacs-lisp/eieio-base.el (eieio-persistent-validate/fix-slot-value):
Check for written representations of objects inside hash tables and
vectors, and reconstruct them.